ANSWER :
a)When spine segments are flexed :
- Internal pressure on a disc increases
- Anterior aspect of the disc is compressed and the nucleus
pulposus gets pressed against annulus fibrosis on the poterior side
of the disc and posterior aspect of the intervertebral space opens
up.
- So, disc bulges posteriorly into the spinal canal.
b)Lifting or carrying a load in front of the body leads to :
- Flexion of the spine which leads to increase in internal disc
pressure from 17psi to 300 psi .
- During flexion when annulus pulposus presses and stretches
tightly over the annulus fibrosis , which becomes thinned and gets
ruptured through which the contents will flow into spinal canal and
leads to compression of spinal cord or nerve roots which causes
risk for further disc pathology.
- So it is better not to do activities associated with spinal
cord flexion.